Data Report No. 0103

William Lutter and Clifford Thurber
(University of Wisconsin-Madison)

1985 Kenya Rift International Seismic Project (KRISP 85)  Teleseismic Experiment
The 1985 Kenya Rift International Seismic Project (KRISP 85) teleseismic experiment consisted of two arrays (Figure 1), a 110 x 100 km two-dimensional array (Green et al., 1991) and a 500-km long E-W linear array (Dahlheim et al., 1985).  Both arrays crossed the central portion of the East Africa rift.  The University of Wisconsin-Madison segment, a 2-dimensional reconnaissance P-wave experiment, was designed to investigate a Bouguer gravity anomaly aligned along the rift axis.  Event data collected by the UW array are being made publicly available through the IRIS DMC as part of an NSF-supported project to archive historic UW-Madison digital seismic datasets collected by the research group of Prof. R. P. Meyer.  In addition, event data from the concurrent E-W linear array are provided with the UW array data.  
The UW teleseismic experiment was positioned to overlay much of the KRISP 85 refraction experiment in order to use the refraction data to constrain teleseismic-derived velocity models (Green, 1993; Green and Meyer, 1992; Green et al., 1991).  The University of Wisconsin-Madison deployed fifteen 3-component digital seismographs in a 110 x 100 km array (Figure 1) from September 1 to December 15, 1985.  Twenty-three sites were occupied due to relocation of several seismographs (see Table 1 for locations of the UW stations).  During the 3 1/2 months of operation of the UW array, 84 teleseisms identified by the USGS (PDE) were recorded by 5 or more UW sites (Table 3).  Of these, 27 events with near-vertical incidence arrivals (PKP) were analyzed by Green and Meyer (1992). 
The University of California Los Angeles (UCLA) simultaneously operated 17 seismograph stations deployed on the E-W linear array which traversed the UW array (Dahlheim et al., 1989).  Data from 12 of these sites (see Table 2 and Figure 1) are provided in this data report along with the UW instrumented data.  Dahlheim et al. (1989) report 40 good quality events were recorded by the UCLA E-W profile.  Data from 52 events are provided with this data report (see Table 4) including 22 events recorded by both arrays.  

Data Collection and Processing
	The University of Wisconsin instruments, equipped with HS10-1 1Hz natural frequency seismometers, were set to selectively trigger on teleseismic events and to record for 160 s at 50 samples/sec.    The data have been assembled in the form of day volumes containing events listed in Table 3.  The UW event data was preserved as SAC files containing station and timing information within the headers.   The UCLA instruments used were 8 UCLA Digital Cartridge tape recorders, 3 Lennartz PCM 5800 and 3 Sprengnether DR100.(Dahlheim et al., 1989) and were set to record at 20 samples/s.  Chronometers were checked every 4 to 8 days using traveling clocks set to Moscow radio time signals (Green, 1991).  SAC file headers contain timing, station, and event information.

Tape Provided
	The data archive consists of one DAT tape with the event- and day-volume data (in SAC format), this report in postscript and RTF formats, and miscellaneous information.

UW Seismic Recorders
	The University of Wisconsin-Madison portable digital seismic recorders are wide-dynamic-range instruments (106 dB) designed for recording seismic waves from earthquakes or explosions (Table 5) [Powell, 1983].  Data from 1-Hz Hall-Sears HS-10-1 geophones were recorded at 50-Hz sampling rates, with a 4-pole Butterworth anti-aliasing filter at 12.5 Hz.  A 13.6 kHz Omega receiver incorporated in each seismograph recorded data from the worldwide Omega navigational network concurrently with seismic signals.  A timing-correction process developed for application to the UW seismic recorders provides 1/4 sample rms time error relative to Universal Time [Schneider et al., 1987].  Ground motion may be estimated from an average value  for voltage sensitivity of 150 V/m/s for the UW Hall-Sears geophones.  

Related publications:
Dahlheim, H., P. Davis, and U. Achauer, Teleseismic investigation of the East African Rift - Kenya, U. J. Afric. Earth Sci., 8, 461-470, 1989.  
Green, W. Verney., Lithospheric Seismic Structure of the Cenozoic Kenya Rift and the Precambrian Midcontinent Rift from Teleseismic Tomography, Ph.D.. Thesis – University of Wisconsin-Madison, 178 pp., 1993
Green, W., and R. Meyer, Array observations of PKP phases across the Kenya Rift:  Implications for structure and tectonics, Tectonophysics, 204, 41-58, 1992.  
Green, W., U. Achauer, and R. Meyer, A three-dimensional seismic image of the crust and upper mantle beneath the Kenya rift, Nature, 354, 199-203, 1991.  
Powell, L.A., Engineering Description of the U.W. Portable Digital Seismograph, Proceedings of the Committee on Controlled Source Seismology (CCSS), Workshop on Portable Digital Seismograph Development, Los Altos, California, 121-122, 1983.  
Schneider, J.F., R.C. Aster, L.A. Powell, and R.P. Meyer, Timing of portable seismographs from Omega navigation signals, Bull. Seismo. Soc. Am., 77, 1457-1478, 1987.  
.

Figure 1.  Map of the 22 UW station (triangle) and 12 of 19 UCLA stations (circle) of the KRISP 85 Teleseismic Experiment are displayed in the lower panel.  The 84 teleseismic events recorded by the UW array (triangle) and 52 events recorded by the UCLA array (circle) are displayed in the upper panel.  Twenty-two events were recorded by both sets of instruments.  These 12 UCLA stations were available from UW tar tapes and are provided in this data report with the archiving of the UW instrumented KRISP85 teleseismic data set.

Table 1. Locations of UW stations deployed in KRISP85 Teleseismic Experiment.  

Station ID	Latitude	Longitude	Elev(m)	Name	
1	-1.438	36.657	1980	Ngong	
2	-1.493	36.481	1020	Emerit	
3	-1.349	36.137	1430	Mosiro	
4	-1.441	35.829	1850	Narosura	
5	-1.054	36.577	1750	Mayer's	
6	-1.058	36.285	1640	Susaa	
7	-1.160	35.917	1910	Narok	
8	-0.810	36.676	2500	South	
9	-0.787	36.285	1920	Naivasha	
10	-0.743	35.973	2770	Suypeo	
11	-0.824	35.906	2460	Enabelibel	
12	-0.584	36.635	2640	North	
13	-0.463	36.223	1790	Elementeita	
14	-0.463	36.036	2060	Kiriri	
15	-0.895	36.090	2880	Melili	
16	-0.744	36.262	1920	Ndabibi	
17	-0.524	36.667	3220	Aberdare	
18	-1.042	36.656	2220	Uplands	
19	-0.744	36.262	1920	Melili	
20	-1.264	36.099	1670	Mosiro	
21	-1.160	35.917	1910	Narok	
22	-1.507	35.756	2000	Narosura	
23	-1.058	36.255	1700	Susua	

Table 2. Locations of UCLA stations deployed in the KRISP85 Teleseismic Experiment.  

StationId	 Latitude	 Longitude	 elev(m)	 Name	
K01	-1.23517	35.023	1680	Masai Mara	
K01	-1.23317	35.0257	1680	After 10/11/85	
K02	-1.18667	35.25	1780	Aitong	
K03	-1.152	35.5833	1925	Ngorengore	
K04	-1.12933	35.782	1920	Narok	
K06	-1.08833	36.4243	1595	Mt.Suswa	
K10	-0.9675	37.4727	1130	Ekarakara	
K11	-0.964	37.7095	1100	Kaewa	
K12	-0.831833	38.0855	960	Mwingi	
K13	-0.83	38.339	770	Nguni	
K15	-0.733	38.8095	570	Katumba	
K16	-0.6275	39.2788	290	Kzzz	
K17	-0.420833	39.6313	140	Garissa	

Table 3. Locations of UW events recorded by the KRISP85 Teleseismic Experiment.  

Id	Name	m:d:yr	hr:mn:sc	latitude	longitude	Depth	Mag	#	Directory	
1	fiji	08:28:85	20:50:49.0	-21.000	-178.990	629	6.1	6	W240	
2	s_sand	08:29:85	06:13:10.8	-57.243	-025.333	50	5.6	5	W241	
3	xinjia	08:29:85	23:39:48.8	39.441	075.452	17	5.2	8	W241	
4	nphili	08:30:85	20:27:10.7	16.982	119.938	29	5.4	8	W242	
5	yunnan	09:01:85	19:07:42.2	23.769	102.738	10	5.0	8	W244	
6	minaha	09:01:85	22:25:34.1	00.665	121.430	83	5.1	9	W244	
7	halmah	09:03:85	23:32:47.5	01.409	128.153	114	5.7	10	W246	
8	banda	09:05:85	03:53:12.0	-07.364	128.472	143	5.3	6	W248	
9	tonga	09:05:85	06:34:58.0	-18.559	-173.632	33	4.6	5	W248	
10	ceram	09:07:85	00:22:01.5	-03.079	130.348	26	5.6	7	W250	
11	ceram	09:07:85	04:40:30.0	-03.136	130.279	24	5.5	7	W250	
12	greece	09:07:85	10:20:50.2	37.445	021.235	31	5.3	8	W250	
13	tonga	09:11:85	17:47:31.0	-15.350	-173.540	30	5.8	10	W254	
14	xinjin	09:11:85	20:45:49.5	39.356	075.407	15	5.8	10	W254	
15	sphili	09:11:85	22:07:10.7	13.594	120.893	135	4.9	7	W254	
16	oaxaca	09:15:85	07:57:53.6	17.980	-097.160	63	6.0	5	W258	
17	tonga	09:15:85	11:25:05.3	-19.220	-175.600	258	5.6	8	W258	
18	tonga	09:15:85	17:31:00.6	-16.800	-174.870	81	5.7	9	W258	
19	sumba	09:15:85	22:58:42.6	-10.809	119.298	39	5.4	5	W258	
20	tonga	09:16:85	02:54:02.0	-15.296	-174.153	139	4.9	7	W259	
21	iran	09:18:85	00:10:34.8	31.627	049.447	33	5.2	5	W261	
22	tonga	09:19:85	08:06:21.0	-18.060	-175.540	302	4.9	7	W262	
23	michoa	09:19:85	13:17:50.1	18.540	-102.553	29	6.4	8	W262	
24	taiwan	09:20:85	15:01:23.5	24.593	122.280	18	5.3	5	W263	
25	guerre	09:21:85	01:37:15.1	17.810	-101.690	42	6.2	7	W264	
26	snatla	09:22:85	18:23:12.2	12.510	-044.316	10	5.7	6	W265	
27	banda	09:24:85	20:28:52.4	-06.405	130.037	147	5.6	9	W267	
28	snatla	09:25:85	07:06:45.7	12.443	-044.333	10	5.3	6	W268	
29	tonga	09:26:85	04:16:22.0	-16.000	-173.200	41	4.7	8	W269	
30	kermad	09:26:85	07:27:47.0	-34.610	-178.570	16	6.4	12	W269	
31	solomo	09:27:85	03:39:08.8	-09.810	159.850	33	6.2	9	W270	
32	tonga	09:27:85	10:10:15.9	-22.179	-174.600	11	6.2	9	W270	
33	crete	09:27:85	16:39:48.7	34.506	026.599	61	5.6	10	W270	
34	tonga	09:28:85	05:50:39.0	-20.910	-174.090	18	5.1	5	W271	
35	yugosl	09:28:85	14:50:15.2	41.581	022.254	7	5.0	9	W271	
36	sphili	10:01:85	10:01:44.8	13.669	120.766	119	4.6	5	W274	
37	hind_k	10:02:85	21:31:36.4	36.473	070.139	217	4.8	6	W275	
38	afghan	10:03:85	18:07:38.2	36.500	071.604	80	5.4	8	W276	
39	malaga	10:04:85	15:17:07.1	-18.304	048.433	10	5.3	8	W277	
40	canada	10:05:85	15:24:02.2	62.237	-124.226	10	6.5	12	W278	
41	vanuat	10:06:85	12:00:49.2	-18.961	169.432	273	5.7	9	W279	
42	java	10:09:85	01:15:04.6	-06.791	107.082	154	5.9	11	W282	
43	alaska	10:09:85	09:33:32.4	54.765	-159.613	30	6.2	9	W282	
44	fiji	10:12:85	02:12:57.9	-21.656	-176.382	155	5.9	11	W285	
45	el_sal	10:12:85	20:29:20.8	13.154	-089.720	42	5.4	5	W285	
46	c_atla	10:12:85	22:20:38.0	00.917	-029.921	10	5.4	9	W285	
47	tajik	10:13:85	15:59:51.2	40.301	069.823	16	5.8	12	W286	
48	nnatla	10:18:85	01:44:28.9	56.757	-034.119	10	5.2	5	W291	
49	carlsb	10:18:85	16:55:30.9	04.454	062.660	10	5.2	6	W291	
50	sphili	10:19:85	20:51:20.8	10.460	125.157	42	5.3	7	W292	
51	kermad	10:20:85	21:36:40.1	-29.012	-178.773	256	5.4	5	W293	
52	java	10:25:85	06:47:04.7	-09.203	105.595	10	5.4	5	W298	
53	banda	10:25:85	18:12:19.5	-07.077	124.284	596	5.9	8	W298	
54	algeri	10:27:85	19:34:57.1	36.460	006.761	10	5.5	9	W300	
55	fiji	10:27:85	22:35:18.0	-17.717	-178.835	565	5.4	7	W300	
56	tanimb	10:28:85	10:28:14.5	-07.331	130.850	33	5.3	5	W301	
57	tonga	10:28:85	12:52:31.2	-15.400	-175.990	33	5.5	8	W301	
58	sumatr	10:29:85	05:19:26.4	-05.713	103.110	33	5.2	8	W302	
59	iran	10:29:85	13:13:44.6	36.681	054.750	53	6.0	5	W302	
60	tonga	11:04:85	22:43:25.0	-17.010	-174.630	144	4.8	7	W308	
61	s_sand	11:06:85	08:15:39.6	-58.716	-026.223	132	5.7	8	W310	
62	tonga	11:06:85	22:16:16.9	-16.370	-173.270	50	5.1	8	W310	
63	turkey	11:07:85	08:26:21.4	40.310	042.307	33	5.1	7	W311	
64	n_zeal	11:07:85	19:12:31.8	-35.210	-179.320	49	6.2	9	W311	
65	timor	11:09:85	12:56:12.1	-09.818	123.739	26	5.5	9	W313	
66	greece	11:09:85	23:30:42.9	41.262	023.988	22	5.4	9	W313	
67	nsatla	11:10:85	19:40:34.0	-29.010	-013.165	10	5.5	8	W314	
68	nsatla	11:14:85	02:11:45.6	-28.912	-013.109	10	5.3	7	W318	
69	ssatla	11:16:85	01:56:43.1	-47.143	-013.397	10	5.2	7	W320	
70	m_indi	11:16:85	04:12:18.8	-38.577	078.368	10	5.8	7	W320	
71	irian	11:17:85	09:40:21.2	-01.639	134.911	10	6.0	5	W321	
72	nsatla	11:18:85	18:18:34.7	-32.298	-013.364	10	5.4	6	W322	
73	java	11:20:85	02:49:44.8	-10.449	111.817	33	5.1	7	W324	
74	moluca	11:21:85	02:27:18.7	02.374	126.729	68	5.4	7	W325	
75	albani	11:21:85	21:57:14.9	41.703	019.388	25	5.5	9	W325	
76	s_sand	11:24:85	21:32:41.8	-59.450	-024.842	37	5.3	5	W328	
77	java	11:25:85	16:26:30.4	-08.649	108.495	68	5.1	5	W329	
78	vanuat	11:28:85	02:25:42.6	-14.030	166.220	33	6.0	6	W332	
79	vanuat	11:28:85	03:49:55.5	-13.980	166.100	43	6.2	6	W332	
80	vanuat	11:28:85	06:37:47.0	-13.850	166.260	25	5.6	6	W332	
81	at-ind	11:30:85	02:28:11.5	-29.235	061.253	10	5.6	6	W334	
82	tonga	11:30:85	03:04:18.8	-16.366	-174.197	165	5.7	6	W334	
83	talaud	12:14:85	06:46:11.7	03.683	126.600	22	5.8	5	W348	
84	arabia	12:14:85	18:13:31.5	14.712	057.999	10	5.5	6	W348	

Table 4. Locations of UCLA events recorded by the KRISP85 Teleseismic Experiment.  

evt	name	lat	lon	depth	yr	day	UW Id	
1	eq8510192051	10.270	125.900	42.0	1985	292	50	
2	eq8510230049	-11.600	125.900	14.0	1985	296		
3	eq8510250647	-9.120	105.350	10.0	1985	298	52	
4	eq8510251812	-7.400	124.170	596.0	1985	298	53	
5	eq8510281028	-7.190	130.510	61.0	1985	301	56	
6	eq8510291313	36.400	54.450	53.0	1985	302	59	
7	eq8511021553	0.000	123.520	119.0	1985	306		
8	eq8511030357	23.350	91.300	33.0	1985	307		
9	eq8511030423	0.170	121.580	157.0	1985	307		
10	eq8511042123	13.400	120.110	77.0	1985	308		
11	eq8511060815	-58.430	-26.130	132.0	1985	310	61	
12	eq8511062216	-16.110	-173.190	33.0	1985	310	62	
13	eq8511071912	-35.150	-179.200	44.0	1985	311	64	
14	eq8511080838	6.370	124.900	46.0	1985	312		
15	eq8511091256	-9.490	123.440	26.0	1985	313	65	
16	eq8511101940	-29.000	-13.900	10.0	1985	314	67	
17	eq8511102046	-6.580	129.110	160.0	1985	314		
18	eq8511111216	-3.200	129.440	73.0	1985	315		
19	eq8511121543	1.540	127.110	114.0	1985	316		
20	eq8511140211	-28.540	-13.600	10.0	1985	318	68	
21	eq8511150539	13.500	-88.410	89.0	1985	319		
22	eq8511151035	-47.130	-13.230	10.0	1985	319		
23	eq8511160156	-47.800	-13.230	10.0	1985	320	69	
24	eq8511162330	-38.340	78.220	10.0	1985	320		
25	eq8511181818	-32.170	-13.210	10.0	1985	322	72	
26	eq8511191403	28.400	128.520	135.0	1985	323		
27	eq8511200249	-10.260	111.490	33.0	1985	324	73	
28	eq8511210227	2.220	126.430	68.0	1985	325	74	
29	eq8511212157	41.420	19.230	25.0	1985	325	75	
30	eq8511241042	9.100	-40.370	10.0	1985	328		
31	eq8511242132	-59.270	-24.500	37.0	1985	328	76	
32	eq8511251626	-8.380	108.290	68.0	1985	329	77	
33	eq8511260027	22.340	121.560	27.0	1985	330		
34	eq8511261005	24.800	125.100	21.0	1985	330		
35	eq8511261323	24.800	125.800	35.0	1985	330		
36	eq8511280349	-13.590	166.110	33.0	1985	332	79	
37	eq8511281740	-8.400	30.000	10.0	1985	332		
38	eq8511300304	-16.220	-174.110	165.0	1985	334	89	
39	eq8512010616	-16.320	66.420	10.0	1985	335		
40	eq8512031242	-11.190	118.150	33.0	1985	337		
41	eq8512072126	0.260	66.590	10.0	1985	341		
42	eq8512081335	30.550	86.350	37.0	1985	342		
43	eq8512081424	30.530	86.320	33.0	1985	342		
44	eq8512091158	-5.390	105.490	148.0	1985	343		
45	eq8512121238	-6.430	108.100	251.0	1985	346		
46	eq8512140646	3.410	126.360	22.0	1985	348	83	
47	eq8512141813	14.420	57.590	10.0	1985	348	84	
48	eq8512170013	-36.000	53.300	10.0	1985	351		
49	eq8512170049	-36.100	53.270	10.0	1985	351		
50	eq8512170654	24.530	67.230	33.0	1985	351		
51	eq8512171447	3.440	126.390	33.0	1985	351		
52	eq8512171456	-4.270	128.250	228.0	1985	351		

Table 5.  General specifications, University of Wisconsin-Madison digital 3-component recorders

DATA STORAGE:		5" reel 1/4" tape, 1800 feet		or	SCSI 3-1/2" disk
CAPACITY:			20 Mbyte					210 Mbyte
FORMAT:			4-track; 3-channel + error correction		multi-stream packet

DYNAMIC RANGE:		106 dB		Noise = 0.25 mV P-P		Clipping = 0.05 V P-P

CALIBRATION:		Random binary sequence and step current applied to seismometer
				coils through a bridge (at programmed start times)

PASSBAND:			Low end:  2 poles at 0.09 Hz
				High end:  4-pole Butterworth at (0.25 * sample rate)

SAMPLE RATE:		25, 50, 100, 200, 400 samples/second

PRE-EVENT DELAY:	512, 1024, 2048 samples/channel

MODES:			Programmed and/or multiple-mode triggered

PROGRAMMING:		Time (ddd – hr:mn:sc), repeat interval and count for run,
				calibrate, trigger arm and disarm (24 entries)

RUN TIMES:			Programmable to 1000 minutes in 1 sec steps with optional
				programmed limits on total recording time for each mode

TRIGGER HARDWARE:	STA/delayed LTA ratio; broadband or teleseismic filtered
TRIGGER SOFTWARE:	Three frequency band Walsh transform filter to discriminate
				teleseismic, regional, and noise; with independent run times

STATUS REVIEW:		Omega signal, time, configuration, schedules, number of events
				recorded and time used for each mode, times of last 500 events,
				seismometer period and damping

TIMING INTERNAL:	1 mHz TCXO, +/- 1 x 10-6 over temperature range
EXTERNAL:			13.6 kHz Omega VLF phase recorded with seismic data; worldwide
				coverage (except Antarctica and central Greenland)
				Post-processing time corrections:  +/- 1 x 10-8 oscillator error; 
				1/4 sample RMS time error relative to U.T.

POWER:			12.5 V DC +/- 20%
				40 ma average current waiting for trigger
				400 ma average current recording to tape
				50 ma average current recording to disk

DIMENSIONS:		56 x 33 x 40 cm

WEIGHT:			22 kg

TEMPERATURE:		0 deg to 50 deg C normal range (tape operates to 0 deg C)
				-20 deg to 70 dec C reduced spec. (disk operates to –20 deg C)
				-40 deg to 80 deg C storage